package com.hmdp.utils;

import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Component;

import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.time.format.DateTimeFormatter;

/**
 * Redis生成全局ID
 */
@Component
public class RedisIdWorker {
    private static final long BEGIN_TIMESTAMP = 1640995200L;
    private StringRedisTemplate stringRedisTemplate;
    private static final int COUNT_BITS = 32;
    public RedisIdWorker(StringRedisTemplate stringRedisTemplate) {
        this.stringRedisTemplate = stringRedisTemplate;
    }

    /**
     * 获取下一个全局唯一ID
     * @param keyPrefix 对应具体业务场景
     * @return
     */
    public long nextId(String keyPrefix){
//        1.生成时间戳
        LocalDateTime now = LocalDateTime.now();
        long nowSecond = now.toEpochSecond(ZoneOffset.UTC);
        long timestamp = nowSecond-BEGIN_TIMESTAMP;
//        2.生成序列号
//        2.获取当前日期 精确到天 加到key上 扩展id的上限
        String date = now.format(DateTimeFormatter.ofPattern("yyyy:MM:dd"));
        long count = stringRedisTemplate.opsForValue().increment("icr:"+keyPrefix+":"+date);

//        3.拼接并返回 时间戳 序列号
        return nowSecond<<COUNT_BITS | count;

    }
    public static void main(String[] args){
        LocalDateTime time = LocalDateTime.of(2022,1,1,0,0,0);
        long second = time.toEpochSecond(ZoneOffset.UTC);
        System.out.println(second);
    }
}
